Merge branch 'stable-2.15'

* stable-2.15:
  ElasticIndexVersionDiscovery: Convert to Java stream API
  ElasticVersionManager: Use correct configuration value for prefix
  Elasticsearch: Refactor generation of bulk requests
  Rename AbstractReindexIT to AbstractReindexTests
  ElasticReindexIT: Use @ConfigSuite.Default instead of @ConfigSuite.Config

Change-Id: Iacd3f2db3728a9c1936170b575016973bf0336d9

java/com/google/gerrit/elasticsearch/bulk/BulkRequest.java

@@ -0,0 +1,43 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.elasticsearch.bulk;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public abstract class BulkRequest {
+
+  private final List<BulkRequest> requests = new ArrayList<>();
+
+  protected BulkRequest() {
+    add(this);
+  }
+
+  public BulkRequest add(BulkRequest request) {
+    requests.add(request);
+    return this;
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder builder = new StringBuilder();
+    for (BulkRequest request : requests) {
+      builder.append(request.getRequest());
+    }
+    return builder.toString();
+  }
+
+  protected abstract String getRequest();
+}